Pressurized fracturing fluids are injected into wells, creating cracks in geological formations, that allow oil and gas to escape through the wall to be collected on the surface. The release of the hydraulic fracturing fluid is a mixture of chemicals, hydrocarbons, natural occurring substances and propants. The design of this process is to remove these materials so that water can be cleaned and can be re-used for additional hydraulic fracturing projects or disposed into a safe above ground environment to be further cleaned to produce clean potable water.
The second application of this technology is the removal of crude oil from water in oil production fields. Oil production wells commonly contain a combination of crude oil and water. In many instances, the produced water from these fields is re-injected back into the underground oil reservoir. The water that is pumped with the crude oil will contain a certain amount of crude oil after the oil/water separation is performed above ground. The separation techniques used is typically a static gravity collection system consisting of large tanks plus an oil water separator system. These techniques require a long retention time in large oil/water tanks.
Alternatively, contaminates from the hydraulic fracturing fluid and the crude oil reservoir water are removed by using a reacting or stripping gas, such as air, carbon dioxide or other gas. In some instances, an air sparged hydrocyclone apparatus is used for the flotation or cleaning of coal, for the flotation or processing of tar sands, and for separating minerals from their host material by flotation. U.S. Pat. Nos. 4,279,743; 4,397,741; and 4,399,027, each issued to Miller, disclose an air sparged hydrocyclone apparatus. The apparatus of Miller does not remove hydrocarbons from water.
Shumeng, et al. disclose a hydrocyclone unit in published Chinese patent application No. 200620148747.2 (Patent ID: CN 200981025 Y). According to Shumeng, et al., the hydrocyclone units is used for separating oil from water. The apparatus of Shumeng, et al. does not utilize negative pressure in conjunction with the apparatus. Nor does the hydrocyclone unit of Shumeng et al. have an unrestricted lower outflow opening. Rather, the lower outflow from the unit restricts flow with a tapered outlet.
Kalnins discloses a hydrocyclone unit in Published PCT application No. WO 88/09696. The hydrocyclone unit utilizes a pressure-reducing device in the form of a venturi positioned at the end of a fluid inlet where inflowing contaminated liquid is introduced to the lower end of the hydrocyclone unit. The negative pressure created by the venturi increases the rate of flow of the inflowing contaminated liquid. Kalnins does not use negative pressure to separate hydrocarbon compounds from liquids, such as water.
Accordingly, none of these references disclose methods of removing hydrocarbon compounds and related products from water according to the present invention.